This invention relates to a scroll compressor used with an air conditioner, a refrigerator, etc., and having a fixed scroll movable in an axial direction.
FIG. 9 is a sectional view of a conventional scroll compressor with a fixed scroll movable in an axial direction shown in Japanese Patent Laid-Open No. Sho 63-80088, wherein numeral 1 is a fixed scroll formed with plate-like spiral teeth 1b on one side of a bed plate 1a. Numeral 2 is an orbiting scroll formed with a plate-like spiral teeth 2b on one side of a bed plate 2a and a projected boss part 2c receiving a driving force of an electric motor 8 from a main shaft 7 on the opposite side. The plate-like spiral teeth 1b of the fixed scroll 1 and the plate-like spiral teeth 2b of the orbiting scroll 2 are used in combination to form a compression space 6.
Numeral 3 is a frame fixedly secured to a closed vessel 9 on the outer periphery of the frame for supporting a thrust load of the orbiting scroll 2 and also supporting the main shaft 7 in the radial direction.
Numeral 10 is a plate spring formed with four drilled holes for bolts with bolts inserted in the two drilled holes at both ends for fixing the plate spring to the upper end face of the extension of the bed plate 1a of the fixed scroll 1 and with bolts inserted in the two drilled holes at the center for fixing the plate spring to the upper end face of the frame 3, whereby the fixed roll 1 and the frame 3 are elastically coupled in the axial direction and fixedly coupled in the radial direction and in the rotation direction around the axis by the plate spring 10.
Numeral 15 is a suction pipe for sucking a low-pressure gas. Numeral 23 is an oil pool for supply to a slide part of a compressor bearing, etc.
The upper part of the bed plate 1a of the fixed scroll 1 defines first and second concentric pistons 31 and 32 fitted so as to slide to first and second concentrically placed cylinder chambers 36 and 37 formed by a cover member 33. The first cylinder chamber 36 is sealed with the second cylinder chamber 37 by a first flexible seal member 34 disposed on the cylindrical face of the first piston 31 and the second cylinder chamber 37 is sealed with the low-pressure side by a second flexible seal member 35 on the cylindrical face of the second piston 32.
Numeral 1c is a discharge port of the fixed scroll. A refrigerant gas compressed in the compression space 6 enters the first cylinder chamber 36 via the discharge port 1c and enters a gas discharge chamber 39 via an opening 38 and is discharged from the discharge chamber 39 through a discharge pipe to the outside of the compressor.
Numeral 1d is an extraction hole through which the compression space during compression communicates with the second cylinder chamber 37 for introducing intermediate-pressure refrigerant gas into the second cylinder chamber 37.
The conventional scroll compressor compresses low-pressure refrigerant gas sucked through the suction pipe 15 by orbiting motion of the orbiting scroll 2 in the compression space 6 and discharges the gas from the discharge port 1c via the first cylinder chamber 36, the opening 38, and the gas discharge chamber 39 to the outside of the compressor through the discharge pipe in the gas discharge chamber 39.
The fixed scroll 1 can be moved axially by elastic deformation of the plate spring 10. Discharge pressure of the first cylinder 36 acts on the first piston 31 and intermediate pressure of the second cylinder 37 acts on the second piston 32, pressing the fixed scroll 1 against the orbiting scroll 2 for energizing sealing between the fixed and orbiting scrolls.
Since the conventional scroll compressor is thus configured, the first flexible seal member 34 for separating discharge pressure and intermediate pressure and the second flexible seal member 35 for separating intermediate pressure and low pressure are disposed in the first piston 31 and the second piston 32 of the upper cylindrical portion of the bed plate 1a of the fixed scroll 1. In this case, there are two cylindrical face fits when the fixed scroll 1 is combined with the cover member 33, and assembly is poor. In addition, there is clearance imbalance in the fit caused by a work error, and a sealing failure in seal points easily occurs.